Controls for refrigerators periodically operate cooling apparatus to cause the temperature of a refrigerated compartment to approach a set point temperature. Typically, in an electronic refrigerator control, the set point temperature is adjustable between upper and lower limits by means of a potentiometer.
Prior refrigerator controls have included means for temporarily resetting the set point temperature to take into account anticipated operational conditions. For example, Schumacher U.S. Pat. No. 4,197,717 discloses a refrigerator control having a user-operable "vacation switch" which, when operated to initiate a vacation mode, increases the temperature set point of the refrigerator so that the refrigerated compartment is maintained at a higher temperature to thereby conserve energy. It is asserted that this increase in compartment temperature does not adversely affect the quality of the food stored therein since the time-averaged compartment temperature following actuation of the vacation switch does not vary substantially from that occuring during normal operation at the lower temperature set point due to the presumed infrequent opening of the compartment door while the refrigerator is operating in the vacation mode. However, it is not clear that food quality is dependent upon the time-average of compartment temperature. Also, the increase in compartment temperature while operating in the vacation mode would seem to be at odds with the needs of most consumers who would justifiably desire food-preservation capabilities to be increased while operating in this mode because the vacation period would extend the amount of time that the food is stored in the refrigerator.
An article in HFD, a Fairchild publication dated Dec. 3, 1984, page 55, discloses a freezer from Magic Chef which has a user-adjustable long-term storage setting that maintains the temperature within the freezer at approximately -10.degree. F. to extend the food storage life.
Stutrud U.S. Pat. No. 3,001,378 and product literature distributed by Sharp (original in the Japanese language together with a partial English translation, copies filed herewith), disclose refrigerator controls having means for lowering the temperature temporarily in one or more compartments. Additionally, the Sharp product literature discloses a manually operable switch for selecting a "moderate operation" function whereby the temperature set point of a compartment is raised to conserve energy.
Tamura et al U.S. Pat. No. 4,298,947 discloses a digital temperature monitor for a refrigerator and Schotten U.S. Pat. No. 4,314,666 discloses a digital temperature set point establishing technique.
Motoyama et al U.S. Pat. No. 4,499,738 discloses a refrigerator control which executes different control routines whereby certain routines are considered preferential in the sense that such routines will continue to completion even if another routine is commanded during such time.